1. Field of the Invention
The present invention relates to a method for controlling phenotypic gene expression of Coryneform bacteria.
2. Description of the Prior Art
Coryneform bacteria are microorganisms which are industrially important. Many Coryneform bacteria which produce large quantities of L-glutamic acid are known, including their mutants producing amino acids such as lysine, etc., and purine nucleotides such as inosinic acid, etc.
On the other hand, breeding and improvement of microorganisms for industrial use utilizing recombinant DNA techniques have been recently attempted in, for example, Escherichia coli. With respect to Coryneform bacteria, some vectors are known as growing in these microorganisms as a host and expressing chemical resistance as a marker (e.g., Published European Patent Application No. 93611), but no method for artificially regulating inserted foreign genes has been discovered. Therefore, it has been difficult to regulate gene expression artificially while expressing foreign genes using Coryneform bacteria as a host.